feat: Gezeiten im Logbuch per Open-Meteo Marine

HW/NW-Felder im Reisetag und Live-Journal mit Server-Proxy auf Basis von
Open-Meteo Marine am GPS-Standort; neueste Position und frischer DB-Stand
vor dem Abruf, Bestätigung nach Übernehmen, Accordion-Layout bereinigt.

Co-authored-by: Cursor <cursoragent@cursor.com>

client/src/utils/tideTurtle.test.ts

@@ -0,0 +1,53 @@
+import { describe, expect, it } from 'vitest'
+import { parseTideTurtleForDate } from './tideTurtle.js'
+
+const sampleNearby = {
+  distanceKm: 1.2,
+  place: { name: 'Kiel' },
+  tides: {
+    data: {
+      timezone: 'Europe/Berlin',
+      extrema: [
+        { time: '2026-06-11T08:50:00.000Z', date: '2026-06-11', height: 0.5, isHigh: true },
+        { time: '2026-06-11T14:34:00.000Z', date: '2026-06-11', height: -0.2, isHigh: false },
+        { time: '2026-06-12T09:00:00.000Z', date: '2026-06-12', height: 0.6, isHigh: true }
+      ]
+    }
+  }
+}
+
+describe('parseTideTurtleForDate', () => {
+  it('returns first high and low on entry date in local timezone', () => {
+    const parsed = parseTideTurtleForDate(sampleNearby, '2026-06-11')
+    expect(parsed.highWater).toBe('10:50')
+    expect(parsed.lowWater).toBe('16:34')
+    expect(parsed.placeName).toBe('Kiel')
+    expect(parsed.distanceKm).toBe(1.2)
+  })
+
+  it('reads Open-Meteo coordinate response without distance', () => {
+    const parsed = parseTideTurtleForDate(
+      {
+        location: { source: 'coordinates', lat: 53.62, lon: 7.15 },
+        tides: sampleNearby.tides
+      },
+      '2026-06-11'
+    )
+    expect(parsed.highWater).toBe('10:50')
+    expect(parsed.distanceKm).toBeUndefined()
+  })
+
+  it('leaves missing tide type empty', () => {
+    const parsed = parseTideTurtleForDate(
+      {
+        data: {
+          timezone: 'UTC',
+          extrema: [{ time: '2026-06-11T12:00:00.000Z', date: '2026-06-11', height: 1, isHigh: true }]
+        }
+      },
+      '2026-06-11'
+    )
+    expect(parsed.highWater).toBe('12:00')
+    expect(parsed.lowWater).toBe('')
+  })
+})